1. Field of Invention
The present invention relates to a drive system for motor-driven household appliances. In particular, the invention relates to a two-speed drive system or gearbox for an appliance in which a drive-outlet is driven at two different speeds in a same rotational direction.
2. Background
In traditional household appliances such as juice extractors, blenders, meal makers, stir cookers, food processors, soymilk makers and soup makers, etc., a common construction includes a motor which is fixed in a unit base, the motor shaft is mounted with a coupling, the blade or tools are directly assembled to the drive outlet, the motor is rotating at a speed that directly drives the blade or tools to process the foods. As different foods need different processing speeds, traditional household appliances have a speed adjusting switch, but its speed is changed by variable voltage. Although this saves energy, it is very low in reliability, the output torque is decreased, the speed is not stable, and it can only process soft foods. Harder foods are very difficult to process, aggravating and damaging the motor as well as the blade or tools of the appliance.
Also, market household appliances are set with different drive outlets that can be connected with different sizes of a blade or tools. Each drive outlet has its different speed to process the food. To process different kinds of foods, the blades or tools need to be changed and connected with the particular drive outlet. During the procedure of blade or tool change, the appliance unit needs to be stopped, thereby making it both inconvenient and a waste of time. In addition, when processing hot foods, changing the blades or tools is both difficult and un-safe.
Therefore, there is a need for an invention concerning a household appliance with a two-speed drive system in which a drive-outlet can be driven at two different speeds in the same rotational direction, where this two-speed drive system cooperates with one-way bearings and a gear system without changing the input voltage. There is a need for such an invention which is further simple in construction, reliable, stable with high torque, convenient to use, and able to process various foods.